On 02.07.2025 16:41, Andrew Cooper wrote: > x86 is the only architecture wanting an optimisation here, but the > test_and_set_bit() is a store into the monitored line
Which is intentional aiui, while this reads as if this was part of the issue. > and is racy with determining whether an IPI can be skipped. Racy here as in limiting the effect of the optimization, but not affecting correctness aiui: If the woken CPU managed to clear the bit already, we'd needlessly IPI it. This could also do with saying. Jan